package com.fang.travel.filter;


import com.alibaba.fastjson.JSON;
import com.fang.travel.common.Result;
import lombok.extern.slf4j.Slf4j;
import org.springframework.util.AntPathMatcher;
import javax.servlet.*;
import javax.servlet.annotation.WebFilter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

/**
 * 检查用户是否已经完成登录
 * 过滤器注解，名称和拦截请求路径
 */

@WebFilter(filterName = "loginCheckFilter",urlPatterns = "/*")
@Slf4j
//实现过滤器接口
public class LoginCheckFilter implements Filter{

    //路径匹配器，支持通配符
    public static final AntPathMatcher PATH_MATCHER = new AntPathMatcher();

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        //1、获取本次请求的URI
        String requestURI = request.getRequestURI();
        log.info("拦截到请求：{}",requestURI);

        //定义不需要处理的请求路径
        String[] urls = new String[]{
                "/favicon.ico",
                "/travelpage/images/**",
                "/travelpage/js/**",
                "/travelpage/css/**",
                "/travelpage/plugins/**",
                "/travelpage/pages/user/login.html",
                "/user/login",

                "/swagger-ui.html/**",     //放行knife4j请求
                "/swagger-resources/**",
                "/v2/api-docs",
                "/v3/api-docs",
                "/v3/api-docs/swagger-config",
                "/webjars/**",
                "/doc.html",
                "/doc.html/**",
        };


        //2、判断本次请求是否需要处理
        boolean check = check(urls, requestURI);

        //3、如果不需要处理，则直接放行
        if(check){
            log.info("本次请求{}不需要处理",requestURI);
            filterChain.doFilter(request,response);  //放行
            return;
        }

        //4、判断登录状态，如果已登录，则直接放行
        if(request.getSession().getAttribute("user") != null){
            log.info("用户已登录，用户id为：{}",request.getSession().getAttribute("user"));
            filterChain.doFilter(request,response);
            return;
        }

        log.info("用户未登录");
        //5、如果未登录则返回未登录结果，通过输出流方式向客户端页面响应数据

        response.getWriter().write(JSON.toJSONString(Result.fail("Error")));
        return;
    }

    /**
     * 路径匹配，检查本次请求是否需要放行
     * @param urls
     * @param requestURI
     * @return
     */
    public boolean check(String[] urls,String requestURI){
        for (String url : urls) {
            boolean match = PATH_MATCHER.match(url, requestURI);
            if(match){
                return true;
            }
        }
        return false;
    }
}
